The overall goal of this study is to link the molecular genetic evolution of Bacillus anthracis to epidemiological models of North American and African anthrax in an effort to better understand the geographic, biotic, and abiotic conditions responsible for outbreaks of anthrax in the world at large and the sources of this pathogen. Towards this end, Dr. Keim and his collaborators will: (1) study the genetic-molecular epidemiology of Bacillus anthracis isolated from different geographic locations and habitats, (2) ascertain the different factors (parameters) that affect the distribution of the molecular markers they employ in their epidemiology surveys and estimate the values of these parameters in laboratory culture. (3) Using Monte Carlo simulations, they will ascertain how the distribution of these markers within and between populations of Bacillus anthracis will be affected by geographic, genetic and ecological processes.